This invention relates in general to vehicles and, in particular, to an engine control system.
More specifically, but without restriction to the particular use which is shown and described, this invention relates to an accelerator/decelerator pedal and system having foot-operated control means to selectively accelerate or decelerate a vehicle engine on a temporary basis to override a hand lever set throttle position.
In operation of many types of construction and industrial machinery, engine speed is controlled by means of a hand lever or throttle generally positioned adjacent to the steering wheel and control lever console of such vehicles. As the vehicle moves or the engine provides an output in response to a particular throttle setting, load and terrain conditions vary whereby it becomes necessary for an operator to accelerate or decelerate the machinery to perform a work task or operate the vehicle safely. For example, the set speed of the throttle may establish a vehicle speed which is too fast to manuever in a curve or down an incline whereby it is necessary that the vehicle be decelerated to operate safely or effectively. In other situations, other conditions may warrant a temporary increase in engine speed or output for efficient operation. After such temporary alteration in engine speed is effected, it is then desirable to resume the normal operation of the vehicle set by the throttle control to maintain the originally selected speed of operation.
To operate construction machinery under actual working conditions, an operator must perform many tasks such as, for example, steering or manipulation of the control levers of the equipment. Because an operator's hands thus may be otherwise occupied, it is inconvenient and impractical to constantly readjust the hand throttle to control engine speed as needed to adjust the variable conditions requiring alteration of engine speed and/or output. Many prior art techniques have been employed by which a foot-operated mehcanism may be operated in a manner to override engine speed, after which release of the pedal resumes the initial hand throttle setting. One known system providing an override capability is disclosed in U.S. Pat. No. 2,821,091 to Benner issued Jan. 28, 1958. Such prior art systems as disclosed in the Benner patent are nevertheless deficient in providing an efficient and convenient foot override pedal while attaining positive and efficient temporary acceleration/deceleration as required.